<?php

    /**
     * PHPExcel_Worksheet_CellIterator
     * Copyright (c) 2006 - 2015 PHPExcel
     * This library is free software; you can redistribute it and/or
     * modify it under the terms of the GNU Lesser General Public
     * License as published by the Free Software Foundation; either
     * version 2.1 of the License, or (at your option) any later version.
     * This library is distributed in the hope that it will be useful,
     * but WITHOUT ANY WARRANTY; without even the implied warranty of
     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     * Lesser General Public License for more details.
     * You should have received a copy of the GNU Lesser General Public
     * License along with this library; if not, write to the Free Software
     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
     * @category   PHPExcel
     * @package    PHPExcel_Worksheet
     * @copyright  Copyright (c) 2006 - 2015 PHPExcel (http://www.codeplex.com/PHPExcel)
     * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt    LGPL
     * @version    ##VERSION##, ##DATE##
     */
    abstract class PHPExcel_Worksheet_CellIterator {
        /**
         * PHPExcel_Worksheet to iterate
         * @var PHPExcel_Worksheet
         */
        protected $subject;
        /**
         * Current iterator position
         * @var mixed
         */
        protected $position = null;
        /**
         * Iterate only existing cells
         * @var boolean
         */
        protected $onlyExistingCells = false;

        /**
         * Destructor
         */
        public function __destruct() {
            unset($this->subject);
        }

        /**
         * Get loop only existing cells
         * @return boolean
         */
        public function getIterateOnlyExistingCells() {
            return $this->onlyExistingCells;
        }

        /**
         * Set the iterator to loop only existing cells
         * @param    boolean $value
         * @throws PHPExcel_Exception
         */
        public function setIterateOnlyExistingCells($value = true) {
            $this->onlyExistingCells = (boolean)$value;
            $this->adjustForExistingOnlyRange();
        }

        /**
         * Validate start/end values for "IterateOnlyExistingCells" mode, and adjust if necessary
         * @throws PHPExcel_Exception
         */
        abstract protected function adjustForExistingOnlyRange();
    }
